The Study On The Improvement Of Thermal Resistance Testing Technology And Core Algorithm In Complex Electronic Devices And Structures

At present,a new generation of semiconductor devices and electronic products play an irreplaceable role in the fields of power electronics,aerospace and new energy vehicles.However,with the development of electronic equipment in the direction of integration,miniaturization and modularization,Their power density is increasing,the heat dissipation environment is becoming more and more complicated,and their thermal reliability problems are becoming more and more serious.The impact of device performance and service life caused by this has become a factor that cannot be ignored that restricts its further development.The junction temperature and thermal resistance measurement in the core area of the device is an important technical means to ensure thermal reliability,and it is also a key indicator for evaluating the thermal performance of electronic equipment.In addition to its own structure,the junction temperature of the core equipment in the electronic system is also related to the heat dissipation path of the equipment,components,modules,heat sinks and other links,and the interface thermal resistance will eventually push up its temperature.It is difficult to achieve accurate non-destructive testing with conventional testing methods in the state of closed device packaging and module integration system applications.The temperature electrical sensitive parameter method based on thermal transient temperature test is one of the effective methods to measure the junction temperature and thermal resistance of electronic devices.It has the advantages of lossless,fast and efficient.However,with the increase in equipment complexity,the application of this method also faces many challenges.This article takes various electronic equipment and modules as the research object,and aims at the application problems of electrical methods in this situation,breaks through its theoretical limitations,develops new measurement methods,and explores its application methods under various complex conditions.The thesis mainly completed the following aspects of work:1.Regarding the limitations of the original structure function method in dealing with "thick and thin" structures,a high-precision thermal resistance extraction algorithm is proposed.When a thin layer of material with high thermal resistance and low heat capacity is located between multiple layers of thicker materials,the traditional structure function method cannot extract the thermal time constant of the material except for the limitation of the processing method.In response to this problem,this thesis proposes a layer-by-layer thermal resistance measurement method,by simulating the thermal time constant spectrum of the previous layer of material on the structure of the heat dissipation path,and eliminating the layer of material in the foster model to avoid back-to-back.The calculation of the time constant of the layer material has an impact,and through multiple iteration calculations to ensure the accuracy of elimination,the thermal resistance of the thin layer material is extracted,which overcomes the limitations of the traditional method.2.Taking a typical special-shaped heat dissipation structure-spiral traveling wave tube as an example,the thermal resistance measurement method based on an external heat source is studied.According to the structural characteristics of the traveling wave tube and the problem of its non-effective temperature-sensitive parameters,a special heat source chip and test probe are designed,which are placed at the heat source of the device under test to simulate the real heat generation of the device,so that the heat can pass through the heat dissipation path of the device diffused into the environment,and quantitatively measured the thermal resistance of the heat dissipation structure.Through this method,the heat dissipation performance of the two main heating components of the traveling wave tube slow-wave structure and the collector is evaluated,and the test equipment is formed to be used in related production units.At the same time,it is also used to measure the heat dissipation performance of other similar special-shaped structures.3.Developed a thermal resistance test system for micro LEDs working with small currents.By solving the technical problems of nano-amp thermal resistance test current generation,high-speed switching under small currents,and high-precision voltage acquisition,a junction temperature and thermal resistance test system for micro LEDs was built.Through this system,micro LED samples of different sizes and substrate materials were measured,and the accuracy of the results was verified by the infrared thermal imaging method.The test system fills the gap in the field of electrical method in the measurement of micro LED devices.4.The thermal performance evaluation methods of power devices under pulsed working conditions are studied.According to the characteristics of the power device in the inverter pulse,the evaluation method of the transient thermal performance of the device under continuous pulse-the thermal resistance measurement and extraction method in the pulse mode was in-depth research,and the pulse thermal resistance based on the thermal time constant spectrum was realized.And the results are compared and verified by various methods such as model simulation,electrical temperature-sensitive parameter measurement of thermal resistance of the device under continuous pulse,and infrared thermal imaging.This article has in-depth research and explored the application of the electrical temperature-sensitive parameter method in many types of electronic devices,perfected the transient temperature rise measurement technology,expanded its application boundary,and some of the results have formed industrialized test instruments that can be directly applied.The analysis of junction temperature and thermal resistance of corresponding devices,materials and heat dissipation structures provides support for device thermal design,reliability analysis and other fields,and has made a certain contribution to the localization of electronic device testing equipment.